Portable hydrogen generator

ABSTRACT

A hydrogen generation system includes a fuel container, a spent fuel container, a catalyst system and a control system for generating hydrogen in a manner which provides for a compact and efficient construction while producing hydrogen from a reaction involving a hydride solution such as sodium borohydride.

FIELD OF THE INVENTION

[0001] Hydrogen is a “clean fuel” because it can be reacted with oxygenin hydrogen-consuming devices, such as a fuel cell or combustion engine,to produce energy and water. Virtually no other reaction byproducts areproduced in the exhaust. As a result, the use of hydrogen as a fueleffectively solves many environmental problems associated with the useof petroleum based fuels. Safe and efficient storage of hydrogen gas is,therefore, essential for many applications that can use hydrogen. Inparticular, minimizing volume and weight of the hydrogen storage systemare important factors in mobile applications.

[0002] Several methods of storing hydrogen currently exist but areeither inadequate or impractical for wide-spread consumer applications.For example, hydrogen can be stored in liquid form at very lowtemperatures. Cryogenic storage, however, only provides a volume densityof 70 grams of hydrogen per liter, which is clearly insufficient forconsumer applications. In addition, the energy consumed in liquefyinghydrogen gas is about 60% of the energy available from the resultinghydrogen. Finally, liquid hydrogen is not safe or practical for mostconsumer applications.

[0003] An alternative is to store hydrogen under high pressure incylinders. However, a 100 pound steel cylinder can only store about onepound of hydrogen at about 2200 psi, which translates into 1% by weightof hydrogen storage. More expensive composite cylinders with specialcompressors can store hydrogen at higher pressures of about 4,500 psi toachieve a more favorable storage ratio of about 4% by weight. Althougheven higher pressures are possible, safety factors and the high amountof energy consumed in achieving such high pressures have compelled asearch for alternative hydrogen storage technologies that are both safeand efficient.

[0004] Other methods of hydrogen storage include the use of chemicalcompounds that either (i) chemically react with water or other speciesto generate hydrogen or (ii) reversibly adsorb and then release thehydrogen. However, these methods and compounds suffer from manydeficiencies, which make them unsuitable for use in consumerapplications. These deficiencies include, high cost, poor safety, poorhydrogen storage capacities, decreased reversibility, poor hydrogengeneration capacities, poor control of hydrogen generation, and highsystem complexities.

[0005] In view of the above, there is a need for safer, more effectivemethods and assemblies for storing and recovering hydrogen. In addition,there is a need to meet the above requirements while minimizing overallsystem volume and weight.

OBJECTS AND SUMMARY OF THE INVENTION

[0006] It is an object of the present invention to provide a compact,safe and efficient system for storing and generating hydrogen. These andother objects of the invention will become more apparent from thedetailed description and examples that follow.

[0007] A first embodiment of the present invention provides a hydrogengenerator system having a first container, a second container, and acatalyst system connected to the first and second containers. A pumpingsystem is provided for pumping fuel from one of the containers throughthe catalyst system. Either container can be a fuel container or a spentfuel container.

[0008] In another embodiment of the present invention, the catalystchamber has a hydrogen generator catalyst for reacting with a fuel suchas a hydride solution to create hydrogen.

[0009] In another embodiment of the present invention, a portion of oneside of the first container is shared with a portion of one side of thesecond container thereby defining a shared partition. The sharedpartition can be flexible, such as by providing the shared partitionwith folding portions or telescoping portions.

[0010] In another embodiment, the hydrogen generator system is providedwith a pressure switch for measuring the pressure within the spent fuelcontainer. The pressure switch is in communication with the pumpingsystem for controlling the pumping depending upon the measured pressureof the spent fuel container.

[0011] In another embodiment of the present invention, the hydrogengenerator system is provided with a hydrogen container connected to thespent fuel container for receiving hydrogen gas byproduct created by thehydrogen generation process.

[0012] In another embodiment of the present invention, the hydrogengenerator system is provided with a hydrogen container which isconnected to the catalyst system for receiving hydrogen gas byproductcreated by the hydrogen generation process.

[0013] In another embodiment of the present invention, the hydrogengenerator system is adapted for a hydride solution such as a metalhydride solution.

[0014] In another embodiment of the present invention, the hydrogengenerator system is adapted for a hydride solution such as a sodiumborohydride solution.

[0015] In another embodiment of the present invention, the hydrogengenerator system is provided with a spent fuel line wrapped around theoutside of one of the containers. In an alternative embodiment of thepresent invention, the first container has a perimeter less than theperimeter of the second container, and the spent fuel line is wrappedaround the portion of the second container.

[0016] In another embodiment of the present invention, an insulated areais provided to cover a portion of the second container and is interposedbetween the second container and the spent fuel line.

[0017] In another embodiment of the present invention, the hydrogengenerator system is provided with the catalyst system and pumping systemdisposed between the first and second containers.

[0018] In another embodiment of the present invention, the hydrogengenerator system is provided with a transportation cart having a frame,a back, at least one support band and a number of wheels. The back canbe provided with a number of support struts, a number of verticalbraces, and bands around the spent fuel tank to hold it to the handtruck and to act as a heat sink.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Further objects, features and advantages of the invention willbecome apparent from the following detailed description taken inconjunction with the accompanying figures showing illustrativeembodiments of the invention, in which:

[0020]FIG. 1 is a cross-sectional view of a portable hydrogen generatoraccording to the invention;

[0021]FIG. 2 is a cross-sectional view of the portable hydrogengenerator having a rigid partition;

[0022]FIG. 3 is a cross-sectional view of the portable hydrogengenerator positioned in a horizontal orientation;

[0023]FIG. 4 is a cross-sectional view of the portable hydrogengenerator having a hydrogen line extending from a catalyst chamber;

[0024]FIG. 5 is a cross-sectional view of the portable hydrogengeneration having a flexible partition;

[0025]FIG. 6 is a side view of a pumping system for the portablehydrogen generation;

[0026]FIG. 7 is a cross-sectional view of a mist filter for the portablehydrogen generation;

[0027]FIG. 8 is a cross-sectional view of an alternative configurationof the portable hydrogen generation; and

[0028]FIG. 9 is a side view of a transportation cart for the portablehydrogen generation.

[0029] Throughout the figures, the same reference numerals andcharacters, unless otherwise stated, are used to denote like features,elements, components or portions of the illustrated embodiments.Moreover, while the subject invention will now be described in detailwith reference to the figures, it is done so in connection with theillustrative embodiments. It is intended that changes and modificationscan be made to the described embodiments without departing from the truescope and spirit of the subject invention as defined by the appendedclaims.

DETAILED DESCRIPTION OF THE INVENTION

[0030]FIG. 1 shows a cross sectional view of a portable hydrogengenerator 100 illustrating one embodiment of the present invention. Theportable hydrogen generator is comprised of a fuel container 101 forcontaining the fuel for the hydrogen generator and a spent fuelcontainer 102 for receiving the resulting products from a hydrogengeneration process.

[0031] The fuel used by the specific embodiment shown in FIG. 1 is ahydride solution and can be a stabilized metal hydride solution. Aprocess for generating hydrogen from such a stabilized metal hydridesolution is described in U.S. patent application Ser. No. 09/979,362filed Jan. 7, 2000, for “A System for Hydrogen Generation” and is herebyincorporated by reference in its entirety. The specific embodiment ofthe invention described herein is adapted for the generation of hydrogenfrom a stabilized metal solution, such as sodium borohydride to producehydrogen gas. Resulting products of the hydrogen generation process caninclude hydrogen gas, borate, and water among other things. It can beappreciated that the specific dimensions as well as operatingtemperatures and pressures of the apparatus can be modified and adaptedaccording to the intended use of the apparatus and according to thespecific metal hydride solution to be used without departing from theintended purpose of the invention. For example, although hydroxide canbe used as a stabilizer, it can be appreciated that a less causticstabilizer such as glycol can be used in the fuel which would allow adifferent choice of materials for components of the apparatus thanspecifically described herein.

[0032] The fuel container 101 and the spent fuel container 102 arepreferably configured to provide an apparatus having a compact andefficient configuration. Accordingly, a portable hydrogen generator 100according to the invention is shown in FIG. 1 having a fuel container101 at least partially integrated with a spent fuel container 102wherein the fuel container 101 has a flexible portion.

[0033] The fuel container 101 and spent fuel container 102 arefabricated as cylinders from material capable of withstanding elevatedpressures and temperatures as well as caustic substances including theintended fuel and fuel byproducts. Specifically, the containers can beconstructed of materials which can withstand temperatures from 0° F. to320° F. and pressures greater than 50 psi or more. Depending on the typeof system the hydrogen generation is to be used with, it can beappreciated that containers can be provided with air circulation portsto permit atmospheric air to freely pass around the spaces surroundingthe pumping and catalyst systems.

[0034] The fuel container 101 is preferably provided with a flexibleportion on one side of the fuel container 101. The flexible portion ofthe fuel container 101 also forms a portion of the spent fuel chamber.Thus, the shared flexible portion forms a flexible partition 118separating the fuel to be contained in the fuel container 101 with theresulting products to be contained in the spent fuel container 102, andthereby provides the portable hydrogen generator 100 with a speciallycompact configuration. Thus, as fuel is used from the fuel container101, the chamber defined by the interior of the fuel container 101 canbe allowed to collapse due to less fuel being present in the fuelcontainer 101. Concurrently, as fuel is used for hydrogen generation andresulting products are accumulated in the spent fuel container 102, thespent fuel chamber is permitted to expand into the space previouslyoccupied by a portion of the collapsing fuel container 101.

[0035] The flexible partition 118 is preferably constructed of aflexible material which can withstand the expected temperatures andcaustic characteristics of the fuel and resulting products. Furthermore,it is believed that the flexible partition is less subject to the highpressure requirements of the outer portions of the fuel and spent fuelcontainers 101, 102 since the relative pressure between the fuel chamberand spent fuel chamber is believed to be less. Nevertheless, to preventrupturing of the flexible partition, the flexible partition is providedto withstand pressures up to 50 psi or more, for the embodiment shown inFIG. 1. Materials from which the flexible partition can be fabricatedinclude, flexible elastomeric material such as nylon thermoplastics suchas PEEK™, Peek, Polysolfoam, polyameride, flexible woven metal, as wellas certain plastics, such as perfluoroalkoxy resins such as Chemfluor®,among other things.

[0036] The flexible partition 118 can be provided with a pleated orcreased portion to facilitate the collapse of the fuel chamber 101 in anaccordion-like manner. It can be appreciated that the position of thefolded portions of the flexible partition, as well as the location ofthe flexible partition 118 between the fuel container 101 and spent fuelcontainer 102 can be modified according to the specific configurationdesired.

[0037] The fuel container 101 can be provided with an aperture forreceiving a dip tub 112 for removal of fuel from the fuel container 101.The fuel container 101 can include a flexible portion at its bottom endand can have a fill aperture 113 for receiving fuel or fuel componentsamong other things. The fill aperture 113 is preferably provided with asealing cap 117 or cover to prevent the contamination of the fuel byforeign substances. The dip tube 112 can alternatively enter the fuelcontainer 101 through the fill aperture 113.

[0038] The dip tube 112 can be fabricated from flexible or rigidmaterial. Such rigid materials include stainless steel, nickel platedalloys, monel, hestoloy, ingonel, high temperature alloys, certainplastics, as well as certain composite materials such as epoxy, graphitefiber, spectra, aramid fibers such as NOMEX®, and KEVLAR® among otherthings. Examples of flexible materials include flexible elastomericmaterial such as nylon, thermoplastics such as PEEK™, Peek Polysolfoam,polyameride, flexible woven metal, as well as certain plastics,perfluoroalkoxy resins such as Chemflour®, among other things. For afuel container 101 having a flexible portion, the dip tube is preferablyfabricated from a flexible material to accommodate any collapse of theflexible portion of the fuel container 101. The dip tube 112 isconnected to the pump 105 at an exit end of the dip tube 112 and extendssubstantially to the bottom of the interior of the fuel container 101whereby substantially all fuel can be withdrawn from the fuel container101 from an entrance end of the dip tube 112. Where a dip tube 112 isformed of flexible material, the dip tube 112 can be provided with aweighted end to ensure that the entrance to the dip tube 112 remains atthe bottom of the interior of the fuel container 101 and the entranceend of the dip tube 112 remains substantially submersed in the fuel.

[0039] In order to provide for equalization of pressure as fuel isremoved from the fuel container 101, an air inlet aperture in the fuelcontainer 101 can be provided. The air inlet aperture can be providedwith an air filter 114 to prevent the fuel from becoming contaminated bythe introduction of foreign substances. The air inlet aperture and airfilter 114 can be provided in the sealing cap 117. The air filter 114can be comprised of material such as stainless steel, polypropylene, orsintered metal.

[0040] The spent fuel container 102 is provided with an apertureproximate to its top end for receiving a spent fuel line 109 for fillingthe spent fuel chamber with resulting products, including a byproductgas such as hydrogen. The spent fuel container 102 is also provided withan aperture proximate to its top end for receiving a hydrogen line 110.The hydrogen line 110 is provided to allow the release of hydrogen gaswhich can accumulate within the spent fuel chamber. The spent fuelcontainer 102 can be provided with an aperture proximate to its bottomend for receiving a waste valve 115 for allowing the drainage of spentfuel and other byproducts from the spent fuel chamber.

[0041] It can be appreciated that the placement of the various aperturesof the system such as the fill aperture, the dip tube aperture, hydrogenline aperture and waste valve aperture can be chosen according to theintended use and configuration of the hydrogen generator apparatus andstill satisfy the intent of the invention. In other embodiments of thepresent invention, these apertures can be placed at other locations onthe fuel container 101 and spent fuel containers 102 such that theapertures can remain proximate to a top side of the apparatus. Forexample, it is believed that placing these apertures at a top side ofthe apparatus can ensure that the resulting product in the spent fuelcontainer 102 remain at the bottom of the spent fuel container 102 dueto the influence of gravity and thus do not interfere with the releaseof hydrogen gas from the hydrogen line 110. Similarly, placing the fillaperture 113 at a top side of the fuel container 101 permits added fuelto accumulate at the bottom of the fuel container 101 while remainingaway from the fill aperture 113. It can be appreciated that othersolutions can be employed to satisfy the purpose of the invention, suchas extending the hydrogen line within the spent fuel container 102 to aportion of the spent fuel chamber where hydrogen gas is expected toaccumulate.

[0042] The spent fuel container 102 is provided with heat fins 103positioned about the outer surface of the spent fuel container 102 toallow any heat built up within the spent fuel chamber to be conveyedaway from the spent fuel chamber thereby cooling the spent fuel chamberand its contents. The heat fins 103 can extend along the outer surfaceof the spent fuel container 102 and can be welded or affixed to theouter surface of the spent fuel container 102 to allow heat to bedissipated from the spent fuel container 102 to the heat fins. The heatfins 103 are preferably fabricated from material having good heatconductive properties, such as copper metal, and can be formed as metaltubes or strips.

[0043] The portable hydrogen generator 100 is further provided with apumping system and a catalyst system. The pumping system provides forthe transfer of fuel from the fuel container 102 to the catalyst systemwhen hydrogen generation is desired. In addition, the pumping system canbe provided for removing fuel from the catalyst system when cessation ofhydrogen generation is desired. The pumping system shown in FIG. 1includes a pump 105 which can be supported by the fuel container 101 ona mounting platform 104 such as a disk. It is not intended that thepumping system and catalyst system be limited to being supported at atop side of the fuel container 101 as shown in FIG. 1. It can beappreciated that other positions for the pumping system and catalystsystem are possible without departing from the intent and purpose of theinvention of maintaining a compact, efficient apparatus. The pump 105can draw fuel from the fuel container 101 via the dip tube 112 asdescribed above.

[0044] Alternatively, the pumping system can be formed with a handoperated pump (not shown) for pumping fuel as well as a set of checkvalves to prevent the back flow of fuel into the fuel container 101. Inaddition, it can be appreciated that a hand pump can be used to startthe generation of hydrogen which can be further perpetuated by theexpected increase of pressure in the spent fuel chamber as resultingproducts are transferred to the spent fuel container 102. Thus, theadded resulting materials can urge the collapse of the flexiblepartition 118 and with the resulting compaction of the fuel container101 additional fuel can be further urged into the catalyst system. Aself-perpetuated reaction can be controlled by the use of a controlvalve before the catalyst system, which control valve can be operatedmanually or by other means.

[0045] The portable hydrogen generator 100 is provided with a catalystsystem, which includes a hydrogen generation catalyst which can beprovided in a catalyst chamber 107. A suitable embodiment of a catalystchamber 107 is described in U.S. patent application Ser. No. 09/979,363filed Jan. 7, 2000, for “A System for Hydrogen Generation” and will bedescribed in greater detail below. The catalyst chamber 107 is providedwith a fuel line 108 for receiving fuel at an entrance end from the pump105. The fuel line 108 is preferably fabricated from a material whichdoes not conduct heat well and can withstand the caustic properties ofthe fuel being used. Examples of such material includepolyvinylchloride, teflon, nylon, polyethylene, polypropylene,Chemflour, Peek™, polysulfone as well as certain gas, oil, and nuclearindustry compliant hoses. An exit end of the fuel line 108 is connectedto an entrance aperture of the catalyst chamber 107 for introducing fuelinto the chamber to contribute to he reaction process. The entranceaperture of the catalyst chamber can be provided with a check valve or acontrol valve (not shown) to control any back flow of fuel or resultingproducts. During the reaction process, resulting products includinghydrogen gas can be passed out an exit aperture of the catalyst chamber107 to a spent fuel line 109.

[0046] A spent fuel line 109 is provided for transporting resultingproducts from the catalyst chamber 107 to the spent fuel container 102.During the reaction process in the catalyst chamber 107, the fuel andresulting products are heated by an exothermic reaction, and thus theresulting products exiting the catalyst chamber 107 from the exitaperture are expected to be at an elevated temperature. Depending uponthe anticipated use of the hydrogen gas, cooling of the gas can beprovided. When the intended use of the hydrogen favors a dry gas,cooling of the resulting products allows moisture to precipitate outinto the spent fuel container 102. Certain applications of the hydrogengenerator can also utilize a hot and moist hydrogen gas, under whichcircumstances cooling is not provided.

[0047] As illustrated in FIGS. 1, 3 and 5, when cool dry gas isdesirable, the spent fuel line 109 can wrap around a portion of the fuelcontainer 101 which is outside the spent fuel container 102 tofacilitate the radiation of heat from the resulting products.Alternatively, the spent fuel line can be provided with a heat sink fortransferring heat. The coiling of the spent fuel line 109 provides asolution which further maintains a compact and simple configuration forthe portable hydrogen generator 100 while facilitating the cooling ofthe resulting products. The spent fuel line 109 is preferably fabricatedfrom a material which can withstand the expected high temperatures andcaustic characteristics of the resulting products. Such materialsinclude stainless steel, nickel plated alloys, certain plastics, as wellas certain composite materials such as epoxy, graphite fiber, spectra,aramid fibers such as NOMEX® and KEVLAR® among other things. It can beappreciated that such materials can be used to coat the inside surfaceof the spent fuel line 109 being formed of other materials. The spentfuel line 109 can also be provided with an outer layer or cover havingfavorable heat conductive properties, such as copper metal, and can beprovided with fins or ridges for radiating heat. It can be appreciatedthat other forms of cooling can be employed to reduced the temperatureof resulting material without departing from the purpose of theinvention.

[0048] Insulation 119 can be provided to separate the spent fuel line109 and the fuel container 101. Insulation 119 can also be provided inother locations such as between the catalyst chamber and the fuelcontainer 101, between the spent fuel line 109 and the hydrogen line110, as well as over portions of the spent fuel container 102. Suchinsulation 119 can be provided of materials including fluoropolymerssuch as nylon, Polysulfone, Teflon® or fiberglass. It can be appreciatedthat other forms of insulation can also be used which fulfill thepurpose of the invention.

[0049] The spent fuel line 109 delivers resulting products to the spentfuel container 102 through an aperture in the spent fuel container 102.The aperture in the spent fuel container 102 is preferably positioned atan upper end of the spent fuel container 102 such that filling of thespent fuel container 102 does not interfere with the delivery ofresulting products via the spent fuel line 109. It is also preferable toseal the junction where the aperture of the spent fuel container 102 andthe spent fuel line 109 meet to prevent uncontrolled release of hydrogengas from the spent fuel container 102.

[0050] The spent fuel line 109 can be provided with a flow restrictor(not shown) at the end of the spent fuel line 109 which enters theaperture of the spent fuel container 102. The flow restrictor canprevent the resulting products from exiting the spent fuel line 109 tooquickly and thereby can ensure sufficient cooling of the resultingproduct by slowing the flow of the resulting products through the spentfuel line 109.

[0051] Before a process of producing hydrogen is commenced, the spentfuel container 102 can be purged of whatever atmospheric or other gasesmay be in the chamber to ensure that during the hydrogen productionprocess the gas exiting from the waste chamber 102 via an entrance endof the hydrogen line 110 is substantially comprised of hydrogen gas.Alternatively, it can be appreciated that the spent fuel container 102can be filled with an inert gas so as not to interfere with the intendeduse of the hydrogen, or the spent fuel container 102 can be partiallyevacuated before the hydrogen generation process is commenced, therebyreducing the need for an initial purging process. As the hydrogenproduction process fill the spent fuel container 102 with resultingproducts including hydrogen gas, the accumulation of these productsincreases the pressure within the spent fuel container 102. As pressureincreases, hydrogen gas which as collected in the spent fuel container102 can be released from the spent fuel container 102 through anentrance end of a hydrogen line 110. The hydrogen line 110 enters thespent fuel container 102 though an aperture in the spent fuel container102 which is preferably sealed at the juncture between the aperture ofthe spent fuel container 102 and the hydrogen line 110. The aperture ofthe spent fuel container 102 through which the hydrogen line 110 entersis preferably provided at an upper end of the spent fuel container 102to prevent the other resulting products which have accumulated in thespent fuel container from interfering with the release of hydrogen gasthough the hydrogen line 110.

[0052] The hydrogen line 110 has an exit end from which the hydrogen gascan be released or collected. The hydrogen line 110 is preferablycomprised of a material which can withstand the high temperatures andpressures which the hydrogen line 110 is expected to be subject to. Suchmaterials include stainless steel, nickel plated alloys, certainplastics, as well as certain composite materials such as epoxy, graphitefiber, spectra, aramid fibers such as NOMEX® and KEVLAR® among otherthings.

[0053] The exit end of the hydrogen line 110 is provided with a controlvalve 116 which can control the release of hydrogen gas from the spentfuel container 102. The hydrogen line 110 can be provided with apressure switch 111 which can control the operation of the pump 105according to the desired operating pressures of the system. As pressurebuilds within the spent fuel container 102 and reaches an upperthreshold pressure, the pressure switch 111 can shut off the pump 105thereby preventing the further flow of fuel to the catalyst system andthereby slowing and stopping the buildup of pressure within the spentfuel container 102. For example, the pressure switch 111 can operate toshut off the pump 105 once a predetermined pressure is reached. Thepredetermined pressure should be within the operating range of thesystem and can be 32 psi. However, it can be appreciated that a hydrogengeneration system according to the invention can also operate atdifferent pressures according to the use of the system. As hydrogen gasis released though the control valve 116, pressure within the spent fuelcontainer 102 is expected to drop. Once the pressure switch 111 detectsthat the pressure had dropped sufficiently, the pressure switch 111 canturn the pump 105 on again to restart pumping of the fuel into thecatalyst system. For example, the pressure switch 111 can turn the pump105 on again once the predetermined pressure is again detected. Thepressure switch 111 can be preset to operate at a fixed pressure or thepressure at which the pressure switch 111 operates can be adjustable. Inaddition, the pressure switch 111 can be a diaphragm type switch or itcan be a solid-state device and can control the pump 105 by eitherelectrical or mechanical connections. The pressure switch 111 cycles thepump 1 05 to operate on and off until the fuel is exhausted. The systemcan be shut off manually or by a hydrogen detector that can shut off thepump 105 when it fails to detect hydrogen at a predetermined minimumthreshold. Such a hydrogen detector can be a fuel cell which produces anelectrical current in the presence of hydrogen gas. A timer and meter(not shown) can also be used to control the flow of fuel to the catalystchamber and provide for a metered flow of fuel to be consumed by thehydrogen generator 100.

[0054] It can be appreciated that alternative configurations of the fuelcontainer 101 and spent fuel container 102 can be used without departingfrom the content and purpose of the present invention.

[0055]FIG. 2 shows a cross-sectional view of a portable hydrogengenerator 100 substantially as described above. In addition, theportable hydrogen generator is provided with a rigid partition 202 forseparating the fuel container 101 and the spent fuel container 102 . Therigid partition 202 can be comprised of the same materials comprisingthe fuel container 101 and the spent fuel container 102. These materialscan include stainless steel, nickel plated alloys, certain plastics aswell as composite materials such as epoxy, graphite fiber, spectra,aramid fibers such as NOMEX® and KEVLAR® among other things. Inaddition, a support 201 is provided for supporting the weight of thefuel container 101.

[0056] An alternative embodiment of the portable hydrogen generatoraccording to the invention is shown in FIG. 3. In FIG. 3, the fuel andspent fuel containers 101, 102 can be placed side by side in ahorizontal position while still maintaining a compact and efficientconfiguration. In a horizontal embodiment in which the fuel and spentfuel containers are placed side-by-side, the flexible partition 118 canbe constructed to collapse in a substantially horizontal direction. Inaddition, the placement of the various apertures of the system,including the fill aperture, the dip tube aperture, the hydrogen lineaperture and waste valve aperture are located to satisfy the intent ofthe invention described above and configured according to the particularembodiment shown in FIG. 3. For example, the spent fuel line 109 can beprovided to extend within the spent fuel chamber so as to deliverresulting products to an area of the spent fuel chamber, where theinitial delivery of resulting products does not interfere with gascollected by the hydrogen line 110.

[0057] An alternative embodiment of the portable hydrogen generatoraccording to the invention is shown in FIG. 4. A separating device 401can be provided near the exit of the catalyst chamber 107 or anywherealong the spent fuel line 109 whereby hydrogen gas can be released intothe hydrogen line 110. Alternatively, the separating device 401 can beprovided by placing an additional exit aperture at the exit end of thecatalyst chamber 107. The separating device 401 selectively passeshydrogen while excluding the other resulting products. Such a separatingdevice 401 can be formed as a membrane having very small pores of a sizeto permit the release of hydrogen gas. Alternatively, the membrane canalso be provided to release steam moisture depending upon the intendeduse of the released gases.

[0058] As shown in FIG. 5, the flexible partition 118 can alternativelybe constructed from a number of partitions 501 or bellows which interactin a telescoping or folding manner to provide a compacting structure.The partition 501 are provided with seals (not shown) for sealing thepartitions 501 of the flexible partition 118. Materials for suchpartitions 501 include the same materials from which the fuel and spentfuel containers can be comprised.

[0059] The pump 105 can be provided as shown in FIG. 6. The pump 105 canbe provided with a drive assembly 601 which can be an electric motor fordriving a drive shaft 602. The drive shaft 602 is attached to ancrankshaft 604 which drives a piston rod 606 of a piston pump 605. Thecrankshaft 604 is rotatably connected to the piston rod 606 by a swivel612 or other rotational connector means. The piston rod 606 is connectedat one end to the piston pump 605 for providing lateral pumping motion.In this manner, the rotational motion of the crankshaft can betranslated into a lateral motion of the piston rod 606 where a choice ofpiston pump 605 requires such a lateral motion for pumping. The pistonpump 605 is flexibly connected to a base 603 by a pivot 607 or otherflexible connection means. The piston pump 605 can be comprised ofmultiple cylinders, each having an individual piston rod 606. A gearreduction assembly [now shown] can be provided connected to the driveassembly 601 for providing more or less torque. It can be appreciatedthat other configurations are possible according to the specific choiceof piston pump 605. Other forms of pumps include diaphragm pumps andcompressors, as well as hand pumps.

[0060] The piston pump 605 can pump fluid by creating cyclicalvariations in pressure at a T-section 608. This fluid can be pumped froman inlet tube 610 to an outlet tube 611 which direction of flow can bedirected by providing one or more check valves 609 which provide forone-way flow of fluid. The inlet tube 610 can be connected to the diptube 112 and the outlet tube 611 can be connected to the fuel line 108.Bi-directional check valves 609 or solenoid valves can also be usedwhich are capable of switching the direction of flow of the fluid whichis to pass through the valves.

[0061]FIG. 6A shows an alternative embodiment of the crankshaft 604 forproviding adjustable pump stroke. The crankshaft 604 can be provided asa plate having an adjustable swivel base 615 for the swivel 612. Theadjustable swivel base 615 is provided with slots into which screws canbe used to slideably adjust the swivel base 615 and for affixing theswivel base 615 to the crankshaft 604.

[0062]FIG. 6B shows an alternative embodiment of the crankshaft 604being provided as a clover-leaf cam for driving the piston rod 606. Thepiston rod 606 is connected to a piston head 613 which is contacted witha spring device 614 for returning the piston rod 606 to a positionagainst the clover-leaf cam on the return stroke.

[0063] The parts of the pump 105 are preferably fabricated frommaterials capable of withstanding the caustic properties of the fuel tobe used. Preferably, the piston pump 605, piston shaft 606, T-section608 and check valves are fabricated from plastics such as PEEK™ andPolysulfone.

[0064] A mist filter 700, shown in FIG. 7A and FIG. 7B, can be providedfor removing moisture and impurities from the gas leaving the hydrogengenerator system. The mist filter 700 includes an outer casing 701having at one end an inlet aperture 706 and at another end, an outletaperture 705. The inlet aperture 706 and outlet apertures can beprovided with a threaded area for receiving a threaded connector forattachment to the hydrogen line 110. Spray plates 702, 703 are providedwithin the mist filter 700 and are connected to the outer casing 701.The spray plates 702, 703 have a plurality of holes or slots 710 whichcan be provided at the periphery of the spray plates 702, 703 such thatgas and moisture entering the mist filter 700 through the inlet apertureis not directly forced against the plurality of slots 710. By providingspray plates 702, 703 in the mist filter 700, three chambers can beformed: a gas-inlet chamber 707, a condensation medium chamber 708 and agas outlet chamber 709. The condensation medium chamber 708 is providedwith a condensation medium 704 which provides a large surface areawithout stopping the flow of the hydrogen gas. A suitable condensationmedium 704 can include small stainless steel shot, as well as plastic,ceramic or other metallic media.

[0065] The inlet aperture 706 can be connected to the hydrogen line 110for receiving moist gas. Moist gas which collects in the inlet chamber707 is sprayed through the slots 710 of the first spray plate 702 intothe condensation medium chamber 708. As the moist gas is sprayed intothe condensation medium chamber 708, the moist gas impinges thecondensation medium 704 causing moisture to condense over the surfacesof the condensations medium 704. This moisture can then flow back intothe inlet chamber 707. This moisture can be collected from the mistfilter 700 and returned to the spent fuel container 102 by the hydrogenline 110 or by a separate line. Moist gas is prevented from exiting thecondensation medium chamber 708 by the second spray plate 703 whichallows the passage of hydrogen gas into the outlet chamber 709. Hydrogengas can then be passed through the outlet aperture 705. The mist filter700 can be provided with a fine molecular sieve in addition or insteadof either the first spray plate 702 or the second spray plate 703 orboth. Alternative forms of filters can also be used such as coalescingfilters.

[0066] An alternative configuration of the portable hydrogen generatoris shown in FIG. 8 in which the catalyst chamber 107 and pumping system105 are provided between the fuel container 101 and spent fuel container102. A heat shield 801 is positioned between the catalyst chamber 107and the fuel container 101. Fuel from the fuel container 101 can be fedby gravity via a fuel line 108 to the catalyst chamber 107 or can bepumped by a pump 105 as described above. Alternatively, the fuelcontainer can be pre-pressurized. A spent fuel line 109 is provided todeliver resulting products to the spent fuel container 102. Moisthydrogen can be collected from the spent fuel container 102 by ahydrogen line 110. The hydrogen line 110 can be coiled around the fuelcontainer 101 to promote the release of heat from the moist hydrogen gasand to permit moisture to flow back into the spent fuel container 102.Alternatively, the hydrogen line 110 can be routed to pass the moisthydrogen gas through a heat exchanger 950. A heat exchanger 950 can beconfigured as shown in FIG. 9c in a parallel manifold array 940 ofparallel tubes to promote the release of heat from the moist hydrogengas to permit condensed moisture to flow more easily back into the spentfuel container. The heat exchanger can be provided within a heat sink908, as shown in FIGS. 9a and 9 b, or it can be provided separately. Theparallel tubes in the heat exchanger 950 can be partially filled withmaterial such as metallic or nonmetallic beads, fibers, wool or chip soas to aid in the condensation and coalescing process of moisture fromthe hydrogen steam. Insulation 119 can be provided between the hydrogenline 110 and the fuel container 101 . Supports 810 are provided tosupport the fuel container 101 and provide an attachment to the spentfuel container 102.

[0067] A cooling fan and cooling coils (not shown) can be added tofurther cool the hydrogen generator 100.

[0068] The portable hydrogen generator can be provided with atransportation cart 900 which can also function as a heat sink as shownin FIGS. 9a and 9 b. The transportation cart 900 is provided with aframe 901, wheels 904 and a back comprised of a plurality of supportstruts 902 connected to the frame 901. The support struts 902 areprovided with a plurality of vertical braces 903 which can be shaped toconform to the shape of the hydrogen generator as shown in FIG. 9athereby providing greater surface contact between the vertical braces903 and hydrogen generator and thus facilitating the transfer of heatfrom the hydrogen generator to the transportation cart 900.Alternatively, or in addition, a heat exchanger 907 can be providedwhich can transfer heat through surface contact with the hydrogengenerator 100 or by having contact with either the spent fuel line 109or the hydrogen line 110. At least one support band 906 is providedconnected to the transportation cart for supporting and holding thehydrogen generator to the transportation cart. Alternatively, or inaddition, a heat sink 908 can be provided for transferring heat from thehydrogen generator 100 and which can provide additional support. Thetransportation cart 900 can be provided with a foot 905 to support thetransportation cart 900 in a standing position. The transportation cart900 can be fabricated from a heat conductive material having structuralrigidity such as metals including steel or aluminum. Handles (not shown)connected to the frame can be provided with insulation to protect anindividual from injury when handling the cart.

[0069] The hydrogen generation systems of the present invention are alsoprovided with a catalyst chamber 107, which includes a hydrogengeneration catalyst. The hydrogen generation catalysts used hereinactivate the reaction of the hydride solution with water to producehydrogen gas. Preferably, these catalyst systems also include acontainment system for the catalyst. A containment system, as usedherein, includes any physical, chemical, electrical, and/or magneticmeans for separating the hydrogen generation catalyst from the reactedmetal hydride solution, e.g., mixture of BO₂ ⁻ and BH₄ ⁻.

[0070] Preferably, the catalyst facilitates both aspects of the reactionof the metal hydride and water: (i) the availability of a hydrogen siteand (ii) the ability to assist in the hydrolysis mechanism, i.e.,reaction with hydrogen atoms of water molecules. Metal hydride solutionsare complex systems having multi-step reduction mechanisms. For example,borohydride has 4 hydrogen atoms and an 8-electron reduction mechanism.Thus, once a single hydrogen atom is removed from a borohydridemolecule, the remaining moiety is unstable and will react with water torelease the remaining hydrogen atoms. Catalysts that are usefulaccording to the present invention include, but are not limited to,transition metals, transition metal borides, alloys of these materials,and mixtures thereof.

[0071] Transition metal catalysts useful in the catalyst systems of thepresent invention are described in U.S. Pat. No. 5,804,329, issued toAmendola, which is incorporated herein by reference in its entirety.Transition metal catalysts, as used herein, are catalysts containingGroup IB to Group VIIIB metals of the periodic table or compounds madefrom these metals. Representative examples of these metals include, butare not limited to, transition metals represented by the copper group,zinc group, scandium group (including lanthanides), titanium group,vanadium group, chromium group, manganese group, iron group, colbaltgroup, and nickel group. Transition metal elements or compounds catalyzechemical reaction (1) and aid in the hydrolysis of water by absorbinghydrogen on their surface in the form of atomic H, i.e., H⁻ or protonichydrogen H⁺. Examples of useful transition metal elements and compoundsinclude, but are not limited to, ruthenium, iron, cobalt, nickel,copper, manganese, rhodium, rhenium, platinum, palladium, chromium,silver, osmium, iridium, borides thereof, alloys thereof, and mixturesthereof. Ruthenium and rhodium are preferred.

[0072] The catalysts used in the catalyst systems of the presentinvention preferably have high surface areas. High surface area, as usedherein, means that the catalyst particles have small average particlessizes. For example, in a system in which the amount of a catalyst is tobe minimized, such as in a system having a disposable catalyst, anaverage diameter can be less than about 100 microns, preferably lessthan about 50 microns, and more preferably less than about 25 micronsthereby reducing cost by requiring less catalyst. The chemical reactionof borohydride and water in the presence of the catalyst follows zeroorder kinetics at all concentrations of borohydride measured, i.e.,volume of hydrogen gas generated is linear with time. It is, therefore,believed that the reaction rate depends primarily on the surface area ofthe catalyst.

[0073] One method of obtaining catalyst particles with high surfaceareas is to use catalysts with small average particle sizes. Althoughcatalyst with small average particle sizes are preferred, smallparticles can be swept away by the liquid metal hydride solution if theyare small enough to pass through the containment system. Suchdeficiencies can be avoided by forming large aggregates of the smallcatalyst particles or by providing a filler to trap these particles.Large aggregate catalyst particles, as used herein, are masses or bodiesformed from any small catalyst particles by well-known powdermetallurgical methods, such as sintering. These metallurgical methodscan also be used in making various convenient shapes. It is believedthat these large aggregate catalyst particles maintain high surfaceareas because they are very porous.

[0074] Alternatively, the hydrogen generation catalysts can be formedinto fine wires or a mesh of fine wires. These fine wires have adiameter of less than about 0.5 mm, preferably less than about 0.2 mm,and more preferably less than about 20 microns. In this embodiment, thefine wires of catalysts do not require a containment system, since thefine wires of catalyst will provide a sufficient surface area forreaction with the metal hydride solution without the particles beingswept away by the liquid metal hydride solution.

[0075] Preferably, the catalyst systems also include a containmentsystem for the catalyst. The containment system employs any physical,chemical, electrical, and/or magnetic means to separate the hydrogengeneration catalyst from the reacted metal hydride solution. As would beevident to one skilled in the art, the need for a particular containmentsystem will depend on the particular application of the system forhydrogen generation. For example, if an uncontrolled supply of hydrogenis needed and no reuse of the system is desired, no containment systemis needed. The stabilized metal hydride solution and the hydrogengeneration catalyst can be separately packaged and combined whenhydrogen is needed. Even this system can be reusable, if the hydrogengeneration catalyst can be later separated to allow regeneration of thereacted metal hydride solution. If a reusable and controllable system isdesired, a containment system can be used to produce hydrogen whenneeded, as described below.

[0076] In one form, the containment system is a liquid and gas permeablemesh that traps or holds particulate catalysts, while allowing liquidsand gases to pass freely through the containment system. In thisembodiment the catalyst particles are larger than the spaces provided bythe containment system. For example, metal hydride solution can flowinto the containment system to react with the catalyst, while oxidizedmetal hydride, hydrogen gas, and unreacted metal hydride can easily passout of the containment system. Alternatively, the containment systemcontaining the catalyst can be lowered into the metal hydride solutionwhen hydrogen is needed.

[0077] In this embodiment, the containment system is a porous or meshmaterial, which is preferably stable in the metal hydride solution.Porous or mesh materials can be formed into any configuration known inthe art, which would keep the catalyst particles in a confined areawhile allowing entry and egress of liquids and gases. For example, apouch or “tea bag” configuration can be used to encapsulate the catalystparticles, while allowing metal hydride solution and hydrogen gas toflow freely there through. Alternatively, The catalyst particles can beencapsulated in a removable tube or cylinder, wherein the ends of thecylinder are covered with the porous or mesh material. Porous or meshmaterial that are useful herein include ceramic, plastic, polymers,nonwovens, wovens, textiles, fabrics, carbons, carbon-fibers, ionexchange resins, metals, alloys, wires, meshes, and combinationsthereof. Typically, the porous or mesh material is in the form of asheet. Nonlimiting examples of porous or mesh material include nylonscreens and stainless steel screens as well as nickel monel.

[0078] In another embodiment, separately packaged metal hydride solutionand hydrogen generation catalyst can be combined when hydrogen isneeded. Upon completion of the reaction, a containment system can thenremove the catalyst by any known separation technique, such ascentrifugation, precipitation, filtration, electrophoresis, andelectromagnetism. For example, metallic hydrogen generation catalystscan be separated by employing a containment system that has a magneticelement. Nonlimiting examples of metallic hydrogen generation catalystsinclude iron, cobalt, nickel, and borides thereof. Alternatively, themixture of catalyst and reacted metal hydride can be flushed out andlater separated by a commercial processing center, which would recoverthe catalyst and regenerate the metal hydride solution.

[0079] In another embodiment, a contained high surface area catalyst canbe obtained by attaching or binding the transition metal catalysts to asuitable substrate. The term “contained high surface area catalyst,” asused herein, means that the catalyst is inherently maintained in acontainment system and not free to migrate by itself, e.g., is attachedto a substrate. In this embodiment, the metal hydride solution can passover and/or through the substrate to react with the bound catalyst.Thus, hydrogen production can be controlled by either contacting orseparating the bound catalyst from the metal hydride solution. If thesubstrate is in particulate form, a further containment system, asdescribed above, is preferred to encapsulate the supported catalyst. Forexample, high surface area transition metal particles can be dispersedonto a solution cast film. Many substrates (e.g., ion exchange resinsand plastics) can be dissolved into a solvent to form a solution ordispersion. The transition metal particles are then added. A solutioncast film can be obtained by evaporating the solvent. The transitionmetal can be added in its salt or metal form and reduction steps can betaken if appropriate, as discussed below.

[0080] In a further example, a contained high surface area catalyst canbe obtained by binding or entrapping a transition metal catalyst ontoand/or within a porous or nonporous substrate by chemical means. Byporous it is meant that the material is liquid and gas permeable.Generally, this process includes (i) dispersing a solution having atransition metal ion onto and/or within a substrate by contacting thesolution with the substrate, and (ii) reducing the dispersed transitionmetal ions to the neutral valence state of the transition metal, i.e.,metallic form. Without wanting to be limited by any one theory, it isbelieved that this unique process binds and/or entraps transition metalcatalyst at a molecular level onto and/or within the substrate. Thesesteps can also be repeated to obtain layers of transition metalmolecules bound onto and/or entrapped within the substrate. High surfacearea substrate bound catalysts can be provided as a porous substratehaving an average diameter of less than about 50 microns. Nonlimitingexamples of porous substrates include ceramics and ionic exchangeresins. Nonlimiting examples of nonporous substrates include metals,wire, metallic meshes, fibers and fibrous materials, such asmonofilaments, threads and ropes fabricated from plastics, nylon,spectra, and aramid fibers such as NOMEX® and KEVLAR®.

[0081] Transition metal ion, as used herein, means an anion, a cation,an anion complex or a cation complex of a transition metal that isdescribed above. Transition metal ions can be obtained from dissolvingsalts of transition metals, which are readily available from commercialmanufacturers, such as Alfa Aesar Company and Aldrich Chemical Company.The transition metal salts may be dissolved in any solvent, typicallywater. The reducing agent can be any material or compound that iscapable of reducing the transition metal ion to its neutral valencestate. Nonlimiting examples of reducing agents include hydrazine,hydrogen gas, glucose hydroxylamine, carbon monoxide, dithionite, sulfurdioxide, borohydride, alcohols and mixtures thereof. Typically, mosttransition metals that catalyze metal hydrides, such as borohydride, canalso be reduced by the same metal hydrides. For example, borohydride isa suitable reducing agent.

[0082] Nonlimiting examples of suitable substrates include ceramics,plastics, polymers, glass, fibers, ropes, nonwovens, wovens, textiles,fabrics, the many forms of carbon and carbon-fibers, ion exchangeresins, metals, alloys, wires, meshes, and combinations thereof.Nonlimiting examples of ceramic substrates with various pore sizesinclude metal oxides, zeolites, perovskites, phosphates, metal wires,metal meshes, and mixtures thereof. Specific examples of suitablesubstrates include, but are not limited to zirconium oxides, titaniumoxides, magnesium oxides, calcium oxides, zeolites, cationic exchangeresins, fibrous materials, nonwovens, wovens, aramid fibers such asKEVLAR® fibers, polytetrafluoroethylene (PTFE) polymers, andcombinations thereof. Since metal hydride solutions can have a high pH,substrates that do not dissolve or react with caustics are preferred.Also preferred are porous substrates with effective surface areas ofgreater than about 50 m²/g or nonporous substrates with an averagediameter or less than about 50 microns.

[0083] When the substrate is in the form of beads, it is preferable tohave the beads in a containment system, as described above, wherein theaverage diameter of the beads is greater than the spaces of thecontainment system. Furthermore, if the substrate has a surfacetreatment, such treatments can be removed by appropriate methods, suchas by boiling or applying a solvent. For example, substrates treatedwith wax can be boiled. Alternatively, the wax can be removed by soapssuch as acetone. Similarly, the starch on textiles can be removed byboiling in water.

[0084] The substrates, except for the ion exchange resins describedbelow, can be treated with the catalyst in the following manner. Thesubstrate is first soaked in a solution containing the transition metalsalt, e.g., ruthenium trichloride. Solutions having concentrations closeto saturation are preferred. This step disperses the transition metalsalt into and/or onto the substrate. The treated substrate is thendried, typically with heat. Optionally, the treated substrate can befiltered before being dried. Note that the treated substrate is notrinsed. It is believed that the drying step promotes absorption of thetransition metal ions onto and/or within the substrate by removing thesolvent. The dry, treated substrate is then subjected to a solutioncontaining a reducing agent, such as sodium borohydride, at aconcentration sufficient to provide complete reduction, e.g., 5% byweight of sodium borohydride. Although this step can be conducted atroom temperature, it is preferred to reduce the absorbed transitionmetal ions at an elevated temperature, e.g., greater than about 30° C.,to increase the reduction rate. It is believed that the reduction stepconverts transition metal ions into its neutral valence state, i.e., themetallic state. After rinsing with water, the substrate is ready for useas a catalyst in the reaction of the metal hydride and water to producehydrogen gas. The method can be repeated to obtain a desired loading oftransition metal onto and/or within the substrate.

[0085] This method to obtain a contained high surface area catalyst canalso be adapted to utilize chemical vapor deposition technology (CVD) byforming a transition metal complex that can be evaporated, i.e., boiledor sublimed, in a vacuum. The transition metal complex includes atransition metal ion, as described above, and a chemical vapordeposition complexing compound. Since the substrate is cold, thetransition metal complex will recondense onto the substrate. Anysuitable substrate, as described above, can be used. Any suitablechemical vapor deposition complexing compound that is known in the artcan also be used. Nonlimiting example of metal complexes useful forchemical vapor deposition are metal diketonates such as Ru(acac) orCo(acac)₃ and metal alkoxides such as Ti(OiPr)₄ (acac=acetylacetonate;OiPr=isopropoxide). The transition metal complex that is deposited onthe substrate can then be reduced by any of the above described reducingagents.

[0086] Alternatively, this method can be adapted to utilizeelectroplating techniques, i.e., electroplating a conductive substratein a solution having a transition metal ion. Useful transition metalions are described above. The transition metal can be electroplated ontoa conductive substrate, such as nickel or stainless steel fine wire,screens comprising such fine wires, or metallic sheets. Typically, suchfine wires can have an average diameter of less than about 20 microns,preferably less than about 10 microns, and more preferably less thanabout 2 microns.

[0087] In one preferred mode of electrochemical plating, a rough coatingis obtained instead of the typical smooth or “bright coatings.” Withoutwanting to be limited by any one theory, it is believed that these roughcoatings have a high surface area. These rough coatings are often blackin color, and are typically referred to in the art of electrochemicalplating by the element name followed by the word “black,” e.g., platinumblack or ruthenium black. Most of the transition metals described abovecan be coated as “transition metal blacks.” The exact conditions mayvary between the elements, but the common parameter is application of avarying voltage during the plating process. “Varying voltage” means thatthe voltage is changed, alternated, stepped up, or stepped down in acyclic or noncyclic manner. For example, a DC voltage can be turned onor off over time. Alternatively, the current can be periodicallyreversed, or the voltage may be switched from a lower to higher voltageand then back to the lower voltage. It is also common to superimpose anAC signal onto a DC source.

[0088] In still another example, this method to obtain a contained highsurface area catalyst can also be adapted to utilize sputter depositiontechnology, e.g., physical vapor deposition, which is well known tothose skilled in the art of surface coating technology. In sputterdeposition, atoms of a metal surface are vaporized by the physicalejection of particles from a surface induced by momentum transfer froman energetic bombarding species, such as an ion or a high-energy neutralatom, preferably an ion or atom from one of the inert noble gases. Thetarget atoms evaporate into the vacuum chamber and then condense on thesubstrate to form a thin film. Typically, the substrate is mounted in asputter chamber, with one side facing up or down toward a hydrogengeneration catalyst target. After evacuating the chamber, an inert gas,such as argon, is used to backfill the chamber to a pressure from about10 to 50 millitorr (from about 1.3 to about 6.7 Pa). The sputteringprocess is initiated by applying a high voltage between the target andthe chamber wall. The sputtering process is continued for an amount oftime (typically a few minutes but can range from less than about aminute up to about a few minutes) according to the desired thickness ofthe hydrogen generation catalyst. Upon completion of the sputtering, airis readmitted into the chamber to remove the coated substrate.

[0089] While most of these substrates simply absorb the solution oftransition metal salts, ion exchange resins offer some surprising andinteresting characteristics. Ion exchange resins are porous polymericmaterials having active groups at the end of the polymer chains.Typically, polymers used in ion exchange resins include, but are notlimited to, polystyrene, epoxy amines, epoxy polyamines, phenolics, andacrylics. Ion exchange resins are classified into anionic exchangeresins and cationic exchange resins. These resins are commerciallyavailable as beads, typically having particle sizes from about 20 meshto about 100 mesh. The resins are also available as sheets and can befabricated into any shape desired.

[0090] Anionic exchange resins attract anions because the active groupsat the ends of the polymers have positive charges. Nonlimiting examplesof positively charged active groups include a quaternary ammonium,tertiary amine, trimethyl benzyl ammonium, and/or dimethyl ethanolbenzyl ammonium. Commercial anionic exchange resins are typicallysupplied in the Cl⁻ or OH⁻ form, i.e., easily replaceable chloride ionsor hydroxide ions are bound to the active groups having positivecharges. Commercially available anionic exchange resins include, but arenot limited to, A-26, A-36, IRA-400 and IRA-900, manufactured by Rohm &Haas, Inc., located in Philadelphia, Pa.; Dowex 1, Dowex 2, Dowex 21 K,Dowex 550A, Dowex MSA-1, and Dowex MSA-2, manufactured by DowCorporation; Duolite A-101 D, Duolite A-102 D, and Duolite A-30 B; andIonac A540, Ionac A-550, and Ionac A-300.

[0091] Cationic exchange resins attract cautions because the activegroups at the ends of the polymers have negative charges. Nonlimitingexamples of negatively charged active groups include sulfonic acid,carboxylic acid, phosphonic acid, and/or aliphatic acid. Commercialcationic exchange resins are typically supplied in the Na⁺ or H⁺ form,i.e., easily replaceable sodium or hydrogen ions are bound to the activegroups having negative charges. Commercially available cationic exchangeresins include, but are not limited to, Nafion resins, manufactured byDupont Corp., located in Wilmington, Del.; IRA-120 and Amberlyst 15manufactured by Rohm & Haas, Inc., located in Philadelphia, Pa.; Dowex22, Dowex 50, Dowex 88, Dowex MPC-1, and Dowex HCR-W2 and Dowex CCR1,manufactured by Dow Corporation; Duolite C-3, Duolite ES-63, and DuoliteES-80; and Ionac 240.

[0092] Anionic exchange resin beads are treated with the catalyst in thefollowing manner. A transition metal salt is dissolved in an acid havingthe corresponding anion that can form an anionic complex of thetransition metal. For example, ruthenium trichloride can be dissolved inhydrochloric acid to form chlororuthenic acid, wherein the ruthenium iscontained in an antionic complex, i.e., [RuCl₆]⁻³. Typically, theanionic complex of a transition metal is characterized by the chemicalformula [M^(y+)X₆]^((y−6)), wherein M is a transition metal, y is thevalence of the transition metal, and X is an anion with a singlenegative charge. The concentration of the transition metal solution canbe varied accordingly, but a concentration close to saturation ispreferred. The acidic solution containing the anionic transition metalcomplex can then be exchanged onto the anionic exchange resin beads bycontacting the anionic exchange resin beads with the anion transitionmetal solution. Typically, this is done either by soaking the beads inthe solution or dropwise adding the solution onto the beads. Withoutwanting to be limited by any one theory, it is believed that the anionassociated with the active group of the resin is exchanged with theanionic transition metal complex. Exchange, as used herein, means thatthe ion associated with the active groups of the ion exchange resin,e.g., the chloride, is substituted with the ion of the transition metal.As a result, a very strong chemical (ionic) bond is formed between theanionic transition metal complex and the active group of the ionexchange resin at each active group site.

[0093] Upon exposure to a reducing agent, such as sodium borohydride,the anionic transition metal complex is reduced at the exchange site toits neutral valence state, i.e., the metallic state. The result is adistribution of transition metal catalyst molecules in and/or on theresin. The process may be repeated to obtain higher metal content ifdesired, because the reduction step restores the anion at the positivelycharged active groups of the exchange resin. It is believed that therestored anion associated with the active group is either the anion thathad been formerly associated with the transition metal, e.g., chloridefrom the [RuCl₆]⁻³, or the reducing agent. After rinsing with water, thetreated anionic exchange resin beads are ready for use as a catalyst inthe reaction of the metal hydride and water to produce hydrogen gas.

[0094] Catalyst treatment of cationic exchange resin beads require aslightly different procedure, because the affinity of the cationtransition metal complexes for the cationic exchange resins is muchweaker than the affinity of anion transition metal complexes for theanionic exchange resins. Despite this additional complication, cationicexchange resins are particularly useful because they can typicallywithstand harsher environments, especially higher temperatures.

[0095] Although transition metals are formally written in their cationicvalence state, e.g. Ru⁺³, transition metals form anionic complexes inthe presence of common complexing ions, such as chloride. Such anionictransition metal complexes would have little or no attraction for acation exchange resin bead having negatively charged active groups. Thiscan be avoided by using transition metal salts having non-complexinganions. Non-complexing anions, as used herein, refers to ions that aretypically very large and contain a central atom that is fullycoordinated, thereby leaving little activity for further complexing withthe transition metal. Nonlimiting examples of non-complexing anions ofthis type include perchlorate (ClO₄ ⁻), hexafluorophosphate (PF₆ ⁻), andtetrafluoroborate (BF₄ ⁻), and mixtures thereof. Transition metal saltshaving non-complexing anions can be obtained via a precipitationreaction with a transition metal salt and an equimolar amount of acompound having a non-complexing anion. The compound having thenon-complexing anion is chosen so that the anion from the transitionmetal salt precipitates out with the cation associated with thenon-complexing anion. For example, a solution of ruthenium trichloridecan be reacted with an equimolar amount of silver perchlorate solution.The chloride will precipitate out of solution as silver chloride andleave ruthenium perchlorate in solution. Since perchlorate ions can notcomplex like chloride ions, only the ruthenium will be hydrated in thecationic form, i.e., [Ru.xH2O]³⁺ wherein x refers to the number of watermolecules. It is believed that the hydrated ruthenium typically has achemical formula [Ru.6H₂O]⁺³.

[0096] The pH of the solution containing both transition metal ion andnon-complexing ion should be adjusted to as close to 7 as possiblewithout precipitation of ruthenium as a hydrated oxide, beforecontacting the cationic exchange resin beads. Preferably, the solutioncontaining the transition metal ion and the non-complexing ion has a pHof greater than or equal to about 2, more preferably greater than orequal to about 4, most preferably greater than or equal to about 7. ThispH adjustment prevents hydrogen cations, H⁺, from competing for cationicsites, i.e., associate with the negatively charge active groups, of thecationic exchange resin. For example, if a 1 Molar solution of rutheniumis used and the pH is 2, ruthenium ions will outnumber hydrogen ions bya factor of 100. Although the ratio of ruthenium ions to hydrogen ionsat pH 2 is sufficient, the ratio would be even better at pH's closer to7. Without wanting to be limited by any one theory, it is believed thatupon contacting the cationic exchange resin beads with the transitionmetal salt solutions, the positively charged transition metal ionsexchange with the positive ions initially associated with the negativelycharged active groups of the cationic exchange resin.

[0097] To ensure high displacements of the transition metal ions withoutusing excessive quantities of transition metal salt solutions, theexchange can be performed by contacting the cationic exchange beads withtransition metal salt solutions in a tube or column. this method canalso be used to treat the previously-described anionic exchange resins.The tube or column is usually mounted vertically and filled withcationic exchange beads. The solution containing transition metal ionsand non-complexing ions is allowed to pass through the column of beads.Typically, more dilute solutions are used first and then progressivelymore concentrated solutions can be used thereafter, thereby allowing theuse of the concentrated solutions from the end of prior batches at thebeginning of subsequent batches. Large quantities of catalyst treatedcationic resin beads can be produced by utilizing a continuouscounter-current system that allows virtually complete utilization ofruthenium and complete saturation of the beads. A continuouscounter-current system means contacting the more dilute rutheniumsolution with the less treated beads and the more concentrated rutheniumsolution with the more treated beads. After exchanging the transitionmetals onto and/or into the beads, the cationic exchange resins arerinsed with deionized water and then reacted with a solution containinga reducing agent, such as sodium borohydride, to reduce the ruthenium toit neutral valence state. Higher transition metal content can beobtained by repeating the exchange and/or reduction steps, because thereduction step restores cations at the negatively charged active groupsof the exchange resin. It is believed that the restored cationassociated with the active group is provided by the reducing agent,i.e., sodium from the sodium borohydride. After rinsing with water, thetreated cationic exchange resin beads are ready for use as a catalyst inthe reaction of the metal hydride and water to produce hydrogen gas.

[0098] Thus, the present invention provides for a hydrogen generationsystem which provides for a compact and efficient construction of ahydrogen generator. Although the present invention has been described inconnection with specific exemplary embodiments, it should be understoodthat various changes, substitutions and alterations can be made to thedisclosed embodiments without departing from the spirit and scope of theinvention as set forth in the appended claims.

We claim
 1. A hydrogen generator system comprising: a first container,said first container having at least one side; a second container, saidsecond container having at least one side; a catalyst system, saidcatalyst system being in fluid communication with said first containerand said second container; a pumping system, said pumping system beingin fluid communication with said catalyst system; wherein at least aportion of said at least one side of said first container is shared withat least a portion of said at least one side of said second containerthereby defining a shared partition, and wherein at least a portion ofsaid shared partition is flexible.
 2. The hydrogen generator systemaccording to claim 1, wherein said flexible portion of said sharedpartition includes folding portions.
 3. The hydrogen generator systemaccording to claim 1, wherein said flexible portion of said sharedpartition includes telescoping portions.
 4. The hydrogen generatorsystem according to claim 1, wherein said first container is a fuelcontainer and said second container is a spent fuel container.
 5. Thehydrogen generator system according to claim 4, further comprising apressure switch, said pressure switch being in fluid communication withsaid spent fuel container and in communication with said pumping system.6. The hydrogen generator system according to claim 4, furthercomprising a hydrogen container in fluid communication with said spentfuel container.
 7. The hydrogen generator system according to claim 1,further comprising a hydrogen container, said hydrogen container beingin fluid communication with said catalyst chamber.
 8. The hydrogengenerator system according to claim 1, wherein said catalyst chamber hasa hydrogen generator catalyst for reacting with a hydride solution tocreate hydrogen.
 9. The hydrogen generator system according to claim 8,wherein said hydride solution is a metal hydride solution.
 10. Thehydrogen generator system according to claim 9, wherein said metalhydride solution is a sodium borohydride solution.
 11. A hydrogengenerator system comprising: a first container, said first containerhaving at least one side; a second container, said second containerhaving at least one side, wherein said second container is contained atleast partially within said first container, and wherein at least aportion of said at least one side of said second container is outsidesaid first container, thereby defining an outside portion; a catalystsystem, said catalyst system being in fluid communication with saidfirst container and said second container; a pumping system, saidpumping system being in fluid communication with said catalyst system;and a spent fuel line, said spent fuel line being in fluid communicationwith said catalyst system and at least a portion of said spent fuel linebeing wrapped around at least a portion of said outside portion of saidsecond container.
 12. The hydrogen generator system according to claim11, wherein said first container has a first perimeter and said secondcontainer has a second perimeter, and said second perimeter being lessthan said first perimeter whereby said spent fuel line being wrappedaround said outside portion of said second container does not extendbeyond said first perimeter.
 13. The hydrogen generator system accordingto claim 11, further comprising an insulated area covering at least aportion of said outer surface area and interposed as least between saidoutside portion of said second container and at least a portion of saidspent fuel line.
 14. The hydrogen generator system according to claim11, wherein said first container is a fuel container, said secondcontainer is a spent fuel container and said spent fuel line is in fluidcommunication with said spent fuel container.
 15. The hydrogen generatorsystem according to claim 11, wherein said second container is a fuelcontainer, said first container is a spent fuel container and said spentfuel line is in fluid communication with said spent fuel container. 16.The hydrogen generator system according to claim 14, further comprisinga pressure switch, said pressure switch being in fluid communicationwith said spent fuel container and in communication with said pumpingsystem.
 17. The hydrogen generator system according to claim 11, furthercomprising a hydrogen container in fluid communication with said spentfuel container.
 18. The hydrogen generator system according to claim 11,further comprising a hydrogen container, said hydrogen container beingin fluid communication with said catalyst chamber.
 19. The hydrogengenerator system according to claim 11, wherein said catalyst chamberhas a hydrogen generator catalyst for reacting with a hydride solutionto create hydrogen.
 20. The hydrogen generator system according to claim17, wherein said hydride solution is a metal hydride solution.
 21. Thehydrogen generator system according to claim 18, wherein said metalhydride solution is a sodium borohydride solution.
 22. A hydrogengenerator system comprising: a first container; a second container; acatalyst system, said catalyst system being in fluid communication withsaid first container and said second container; a pumping system, saidpumping system being in fluid communication with said catalyst system;and a spent fuel line, said spent fuel line being in fluid communicationwith said catalyst system and at least a portion of said spent fuel linebeing wrapped around at least a portion of said outside portion of saidsecond container, wherein said catalyst system and said pumping systemare disposed between said first container and said second container. 23.The hydrogen generator system according to claim 22 further comprising atransportation cart having a frame, a back, at least one support bandand a plurality of wheels, wherein said back and said at least onesupport band support said first container and said second container. 24.The hydrogen generator system according to claim 22 wherein said back iscomprised or a plurality of support struts and a plurality of verticalbraces.